Exploring focal and aberration properties of electrostatic lenses through computer simulation

The interactive nature of computer simulation allows students to develop a deeper understanding of the laws of charged particle optics. Here, the use of commercially available optical design programs is described as a tool to aid in solving charged particle optics problems. We describe simple and practical demonstrations of basic electrostatic lens properties, such as the determination of focal points, magnification and aberration coefficients, as well as illustrate basic theorems (the Helmholtz-Lagrange law and Snell's law) and plotting typical lens curves. Throughout this investigation, students are encouraged to make connections between light and charged particle optics.